Wireless Communication Subsystem with a Digital Interface

ABSTRACT

Systems and methods are disclosed which provide wireless communication systems implementing subsystems adapted for flexible deployment configurations and to resist the introduction of interference. Preferred embodiments of the present invention provide a wireless communication system configuration in which an ODU subsystem is coupled to an IDU subsystem using a fiber optic link. According to a preferred embodiment of the present invention, an ODU subsystem is adapted to provide conversion between digital and analog to thereby facilitate the use of a digital link between the ODU subsystem and a corresponding IDU subsystem. Embodiments of the present invention utilize a plurality of ODU subsystems configured according to the present invention to provide wireless communication coverage of a service area, such as to provide a wireless application termination system (WATS) hub for use in providing wireless communication links with respect to a plurality of subscriber units.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 13/687,880, filed Nov. 28, 2012 and entitled “WIRELESSCOMMUNICATION SUBSYSTEM WITH A DIGITAL INTERFACE,” which is acontinuation of U.S. patent application Ser. No. 11/637,366, entitled“WIRELESS COMMUNICATION SUBSYSTEM WITH A DIGITAL INTERFACE,” filed Dec.12, 2006 and issued Jan. 1, 2013 as U.S. Pat. No. 8,345,698, which is adivision of U.S. patent application Ser. No. 10/010,935, entitled“WIRELESS COMMUNICATION SUBSYSTEM WITH A DIGITAL INTERFACE”, filed Dec.5, 2001, and issued Aug. 10, 2010 as U.S. Pat. No. 7,773,614, thedisclosures of which are incorporated herein by reference in theirentirety.

TECHNICAL FIELD

The invention relates generally to wireless communication systems and,more particularly, to configurations of wireless communication systemsemploying a digital interface between an outdoor unit and an indoorunit.

BACKGROUND OF THE INVENTION

Currently there is substantial demand for fixed wireless communicationsystems providing relatively high speed and/or high data capacity fromlocation to location. For example, some Internet infrastructureproviders and competitive local exchange carriers (CLEC) provideso-called “last mile” and “last foot” wireless transmission systemsusing radio frequency (RF) transmissions to bridge gaps in the availablecopper or coaxial wire and fiber optic cable.

Conventionally these RF transmission systems have operated in themicrowave or millimeter wave frequencies, such as through the use ofpoint-to-point or point-to-consecutive point systems operating in the27-38 GHz bands. Additionally, Multichannel Multipoint DistributionSystem (MMDS) frequency bands at 2.1 to 2.7 GHz may be employed for datacommunications as well as bands known as the 3.5 GHz bands. Morerecently, frequencies in the 5 GHz band have been freed for use in highspeed and/or high data capacity transmissions. Specifically, the UnitedStates Federal Communications Commission (FCC) created a wireless arenacalled the Unlicensed National Information Infrastructure (U-NII)setting forth three sub-bands (5.15 to 5.25 GHz, 5.25 to 5.35 GHz, and5.725 to 5.825 GHz) available for wireless communication withoutacquiring a license. Systems and methods specifically adapted for use insuch unlicensed bands are shown and described in the above referencedapplications entitled “System and Method for Mitigating Data FlowControl Problems in the Presence of Certain Interference Parameters,”“System and Method for Statistically Directing Automatic Gain Control,”and “System and Method for Adapting RF Transmissions to Mitigate theEffects of Certain Interferences.”

Beyond the licensing, availability, and interference issues associatedwith the particular spectrum utilized for such wireless communications,many challenges face those seeking to establish reliable and economicwireless communication infrastructure. For example, wirelesscommunication systems often must be configured to allow the deploymentof an antenna or antenna array at a suitable elevation and/or having asubstantially clear line of sight, such as by positioning an outdoorunit (ODU) on a roof top or on a mast. Various electrical componentscoupled thereto may be deployed at some distance, such as deploying anindoor unit (IDU) within the confines of a building or associated radioshack. Often the separation of such components results in degradedcommunication quality, reliability, and/or configuration flexibility.For example, transmission lines coupling prior art ODUs and IDUs areoften prone to the introduction of interference and/or attenuation ofsignals conducted therethrough. Additionally, the links employedaccording to the prior art, typically coaxial cables, present a singlepoint of failure, such as may occur due to relatively minor physicaldamage, and are often quite bulky and resistant to turning tightradiuses, requiring large minimum radiuses and other deploymentnecessities. Moreover, the distance by which an ODU and correspondingIDU may be separated has typically been relatively limited according tothe prior art.

In addition to the aforementioned challenges associated with deploying aconfiguration of a prior art ODU and IDU, challenges with respect toestablishing reliable and economic wireless communication infrastructureoften include the ability to provide suitable communication coverage ofa service area. For example, prior art ODUs are typically relativelylarge devices, generally requiring appreciable space and structure fortheir deployment, and therefore are less than ideal for configurationsin which a number of such systems are disposed to illuminate arelatively large service area, such as that associated with apoint-to-multipoint base station or hub.

Accordingly, a need exists in the art for systems and methods whichprovide reliable and/or economic wireless communication infrastructure,such as through the use of systems configured to facilitate flexibilitywith respect to deployment and connecting of subsystems thereof.Moreover, a need exists in the art for such systems and methods toresist the introduction of interference and/or provide for faulttolerance.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to systems and methods which provide awireless communication system implementing subsystems which are adaptedfor relatively flexible deployment configurations and which are adaptedto resist the introduction of interference. Preferably these wirelesscommunications systems generally employ frequencies in the range of 2 to11 GHz. Included in this band are the sub-bands of the U-NII, MMDS,Wireless Communications Service (WCS) and 3.5 GHz bands. Preferredembodiments of the present invention provide a wireless communicationsystem configuration in which an ODU subsystem is coupled to an IDUsubsystem using a fiber optic link. Preferably, the use of such a fiberoptic link according to the present invention allows flexibility in theconfigurations in which the ODU and IDU subsystems may be deployed, bothin separation distance and in the physical attributes of the environmentwhich may be acceptably accommodated.

According to a preferred embodiment of the present invention, an ODUsubsystem is adapted to provide conversion between digital and analog tothereby facilitate the use of a digital link between the ODU subsystemand a corresponding IDU subsystem. Such an ODU subsystem configurationprovides advantages in that the RF signals of the wireless communicationlink, which are generally susceptible to interference, are relativelyquickly converted to a digital signal for further processing. Moreover,the multiplexing of such a digital signal with other signals which maybe communicated between the ODU subsystem and IDU subsystem, such ascontrol and/or timing signals or other overhead information, issimplified, allowing for an ODU subsystem physically smaller andsimplified, at least with respect to particular aspects, as compared totypical prior art ODU configurations.

The preferred embodiment fiber optic link between the ODU subsystem andthe IDU subsystem presents less bulk than that of conventional RF links,such as the aforementioned coaxial cable, which is of substantial sizewhen provided in a low loss configuration. Further, such a link issubstantially immune to the introduction of interference energy andallows for relatively long distances to be traversed between an ODUsubsystem and an IDU subsystem of the present invention.

Embodiments of the present invention utilize a plurality of ODUsubsystems configured according to the present invention to providewireless communication coverage of a service area, such as to provide awireless application termination system (WATS) hub for use in providingwireless communication links with respect to a plurality of wirelesssubscriber units. The relatively small ODU subsystems of a preferredembodiment are particularly well suited for such deployments. Moreover,the preferred embodiment fiber optic ODU subsystem/IDU subsysteminterface of the present invention facilitates the use of one, or arelatively few, links between such subsystems even when deployed in ahub configuration.

A single fiber optic link may be relied upon to provide bandwidthsufficient to carry data associated with the wireless links of aplurality of ODU subsystems of the present invention. Accordingly, apreferred embodiment of the present invention includes a single fiberoptic link between an IDU subsystem location and an ODU subsystemlocation. A plurality of ODU subsystems may be coupled to this linkusing signal splitting and/or switching technology. For example,according to an embodiment of the present invention, a plurality of ODUsubsystems deployed on a common rooftop are coupled together, e.g., indaisy chain fashion, to share a single fiber optic link with acorresponding IDU subsystem or subsystems.

Preferred embodiments of the present invention provide fault tolerantconfigurations. For example, an embodiment of the present inventionprovides at least two fiber optic links between an IDU subsystemlocation and an ODU subsystem location. Accordingly, a fiber optic ringarchitecture, such as a resilient ring topology, may be deployed withrespect to the IDU subsystem and ODU subsystem link of the presentinvention.

The foregoing has outlined rather broadly the features and technicaladvantages of the present invention in order that the detaileddescription of the invention that follows may be better understood.Additional features and advantages of the invention will be describedhereinafter which form the subject of the claims of the invention. Itshould be appreciated by those skilled in the art that the conceptionand specific embodiment disclosed may be readily utilized as a basis formodifying or designing other structures for carrying out the samepurposes of the present invention. It should also be realized by thoseskilled in the art that such equivalent constructions do not depart fromthe spirit and scope of the invention as set forth in the appendedclaims. The novel features which are believed to be characteristic ofthe invention, both as to its organization and method of operation,together with further objects and advantages will be better understoodfrom the following description when considered in connection with theaccompanying figures. It is to be expressly understood, however, thateach of the figures is provided for the purpose of illustration anddescription only and is not intended as a definition of the limits ofthe present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention, reference isnow made to the following descriptions taken in conjunction with theaccompanying drawings, in which:

FIG. 1 shows a typical prior art wireless communication systemconfiguration for use in point-to-point communications;

FIG. 2 shows a preferred embodiment wireless communication system of thepresent invention; and

FIG. 3 shows an alternative embodiment wireless communication system ofthe present invention.

DETAILED DESCRIPTION OF THE INVENTION

Directing attention to FIG. 1, a prior art wireless communication systememploying a substantially conventional indoor unit (IDU) and outdoorunit (ODU) configuration is shown. Specifically, wireless communicationsystem 100, such as may be utilized in providing one end of a broadbandwireless communication link, includes IDU 101 and ODU 102. Subscriberdata is provided to/from IDU 101 through subscriber data interface 150,such as may be coupled to a network or customer premise equipment.Correspondingly, subscriber data is provided to/from ODU 102 through RFantenna 130, such as may be in wireless communication with a similarlyconfigured wireless communication system. IDU 101 and ODU 102 areprovided an information communication link by coaxial cable 140.

The illustrated embodiment of prior art IDU 101 includes orthogonalfrequency division multiplex (OFDM) modem 111 coupled to subscriber datainterface 150 to accept/provide digital subscriber data communicationthereto. OFDM modem 111 includes digital to analog and analog to digitalcircuitry, D/A 112 and A/D 113 respectively, to provide conversion ofsubscriber data between digital and analog formats, e.g., conversionbetween digital Internet protocol (IP) and an analog baseband frequency.OFDM modem 111 is coupled to hexiplexer 114 to providemultiplexing/demultiplexing of analog signals communicated between IDU101 and ODU 102, such as by the use of relatively complicated frequencydivision multiplexing. Hexiplexer 114 is coupled to frequency converter115 providing frequency conversion between the analog baseband frequencyand an analog intermediate frequency. Frequency converter 115 is coupledto coaxial cable 140 providing communication of analog intermediatefrequency signals between IDU 101 and ODU 102.

The illustrated embodiment of prior art ODU 102 includes frequencyconverter 125 providing frequency conversion between the analogintermediate frequency and an analog RF frequency. As with frequencyconverter 115 of IDU 101, frequency converter 125 of ODU 102 providescommunication of analog intermediate frequency signals between ODU 102and IDU 101. Frequency converter 125 is coupled to hexiplexer 124 toprovide multiplexing/demultiplexing of analog signals communicatedbetween ODU 102 and IDU 101, using frequency division multiplexingtechniques. Hexiplexer 124 is coupled to RF front end 121. RF front end121 is coupled to RF antenna 130 to transmit/receive analog subscriberdata associated with wireless communication.

The above described substantially conventional wireless communicationsystem configuration suffers from several disadvantages. For example,the coaxial cable link between the IDU and the ODU is relatively limitedin the distances that may be traversed before unacceptable signalquality is experienced. Moreover, such coaxial cables are typicallylossy and/or of considerable bulk. Such cables, therefore, presentdifficulties in their being routed in many situations, such as whererelatively tight radius corners are required or where unobtrusive cableruns are desired. Additionally, such cables are typically relativelysusceptible to damage resulting in degradation of signal transmissionattributes. For example, due to the bulk of the cable it may be moreprone to damage at various points along a cable run. Coaxial cable isparticularly susceptible to performance degradation associated withseemingly minor damage to insulating layers. For example, an outerinsulating layer may be punctured and, although not directly impingingupon the conductors contained therein, may allow infiltration ofmoisture changing dielectric properties of the coaxial cable and/orcorroding the conductive material, resulting in performance degradation.Moreover, coax connectors used with such coaxial cable are susceptibleto moisture infiltration and corrosion which not only results in signaldegradation, but which may also result in equipment damage.

The transmission of analog signals, such as the aforementioned analogintermediate frequency between the IDU and ODU, is prone to signaldegradation, such as associated with noise and interference energy. Forexample, the coaxial cable linking the IDU and ODU may be routed nearsources of electromagnetic energy, such as electric motors ortransformers, resulting in degradation of the signals transmittedtherethrough. Similarly, the analog circuitry of the IDU and ODU maycontribute to signal degradation if not properly shielded or otherwiseisolated. Analog multiplexing circuits are generally subject to driftdue to aging, temperature fluctuations and other environmental factorssuch as humidity. Additionally such analog multiplexing circuitsfunction differently from unit-to-unit due to component manufacturingtolerances.

A further disadvantage of the substantially conventional configurationillustrated in FIG. 1 is that the ODU is typically relatively large andcomplicated, perhaps even employing a climate control system. Forexample, the illustrated hexiplexer circuitry employing frequencydivision multiplexing is difficult to implement and must typically bephysically large in order to minimize signal attenuation and/or theintroduction of noise.

The foregoing notwithstanding, it should be appreciated that theconfiguration shown in FIG. 1 provides certain advantages which have ledto conventional implementations to adopt such a configuration. In theconfiguration of FIG. 1, hexiplexers 114 and 124 combine/separate DCpower (PWR), subscriber data receive and transmit signals, clock signal,and blanking signal for communication via coaxial cable 140.

Directing attention to FIG. 2, a preferred embodiment configuration of awireless communication system adapted according to the present inventionis shown. Specifically, wireless communication system 200, such as maybe utilized in providing one end of a broadband wireless communicationlink, e.g., a base station hub, includes IDU subsystem 201 and ODUsubsystem 202. Subscriber data is provided to/from IDU subsystem 201through subscriber data interface 250, such as may be coupled to anynumber of devices, including switches, routers, multiplexers, and/orcustomer premise equipment; or networks or other communicationbackbones, including the public switched telephone network (PSTN), theInternet, a local area network (LAN), metropolitan area network (MAN) orwide area network (WAN). Correspondingly, subscriber data is providedto/from ODU subsystem 202 through RF antenna 230, which may be inwireless communication with any number of devices, including a similarlyconfigured wireless communication system, a subscriber system, or thelike. Notably, in the configuration of FIG. 2, IDU subsystem 201 and ODUsubsystem 202 are provided an information communication link by fiberoptic cable 240.

According to a preferred embodiment configuration of FIG. 2, all analogsignal processing associated with the wireless link provided by wirelesscommunication system 200 is isolated within ODU subsystem 202.Accordingly, IDU subsystem 201 of the preferred embodiment provides onlydigital signal processing. Correspondingly, fiber optic cable 240 of thepreferred embodiment provides a digital signal link between IDUsubsystem 201 and ODU subsystem 202 of communication system 200.

Accordingly, the illustrated embodiment of IDU subsystem 201 includesOFDM digital modem 211, preferably including substantially only thosecircuit components of an OFDM modem utilized with respect to digitalprocessing of signals. OFDM digital modem 211 is preferably coupled tosubscriber data interface 250 to accept/provide digital subscriber datacommunication thereto. Subscriber data as provided to/from subscriberdata interface 250 may be in any of a plurality of data transmissionformats, including but not limited to T1, T3, E1, E3, OC-1, OC-3, OC-12,ISDN, Ethernet, and SONET. OFDM digital modem 211 is preferably coupledto digital multiplexer 214 to provide multiplexing/demultiplexing ofdigital signals communicated between IDU subsystem 201 and ODU subsystem202. Such signals may include subscriber data forward link (transmit)and/or reverse link (receive) as well as various control and overheadsignals, such as communication system operation, maintenance, andconfiguration signals, transmitter control signals, and/or timingsignals. Digital multiplexer 214 is preferably coupled to fiberinterface 216 which provides arbitration between digital signalstransmitted between the different media of the fiber optic cable andelectronic circuitry internal to IDU subsystem 201. Accordingly, fiberinterface 216 is coupled to fiber optic cable 240 providingcommunication of digital signals between IDU subsystem 201 and ODUsubsystem 202.

The illustrated embodiment of ODU subsystem 202 includes fiber interface226 providing arbitration between digital signals transmitted betweenthe different media of the fiber optic cable and electronic circuitryinternal to ODU subsystem 202. As with fiber interface 216 of IDUsubsystem 201, fiber interface 226 of ODU subsystem 202 providescommunication of digital signals between ODU subsystem 202 and IDUsubsystem 201. Fiber interface 226 is coupled to digital multiplexer 224to provide multiplexing/demultiplexing of digital signals communicatedbetween ODU subsystem 202 and IDU subsystem 201. Digital multiplexer 224is preferably coupled to digital to analog and analog to digitalcircuitry, D/A 222 and A/D 223 respectively, to provide conversion ofsubscriber data between digital and analog formats, e.g., conversionbetween digital Internet protocol (IP) and an analog baseband orintermediate frequency. D/A 222 and A/D 223 of the illustratedembodiment are coupled to frequency converter 225 preferably providingfrequency conversion between an analog intermediate frequency and ananalog RF frequency. Frequency converter 225 is preferably coupled to RFfront end 221 which, in turn, is preferably coupled to RF antenna 230 toreceive/transmit analog subscriber data associated with wirelesscommunication. Amplifiers may be employed to enhance signal strength inthe present system. Preferably such amplifiers are employed inassociation with converter 225.

It should be appreciated that the above described preferred embodimentisolates processing of analog signals to within the ODU subsystem.Specifically, RF and IF analog signal processing is accomplished in theODU subsystem and, therefore, only digital signal processing is providedby the IDU subsystem of the preferred embodiment. This configurationprovides several advantages. For example, analog signals are oftensubject to degradation, such as associated with signal attenuationand/or the introduction of noise or interference energy. However, thepreferred embodiment illustrated above is configured to convert areceived analog signal to digital as quickly as is practicable.Similarly, the preferred embodiment converts a transmitted digitalsignal to analog at a point very close to the actual wirelesscommunication of the signal to thereby minimize signal degradationassociated with analog transmission. Moreover, the integrity of theinformation carried in a digital signal is easier to verify and/ormaintain and, thus, the preferred embodiment provides an architecture inwhich a high degree of data reliability is maintained.

A further synergistic advantage of the preferred embodiment illustratedabove is that consolidation of the analog signal processing within theODU subsystem allows for better shielding of the analog signals.Specifically, the multiplexing of digital signals may be providedthrough the use of integrated circuit components requiring little spaceand dissipating relatively little heat.

Additionally, the digital fiber optic link between the IDU subsystem andODU subsystem of the illustrated embodiment allows for relatively longdistances to be traversed therebetween. Accordingly, an ODU subsystem ofthis embodiment may be easily deployed upon the roof of a building, andthe operator provided with the freedom to dispose the IDU subsystemalmost anywhere within the building that is available to him, includingthe basement of a high-rise tower. This is in addition to the advantagesassociated with the relatively small diameter and flexibility of thefiber link, which allows its relatively easy deployment in a number ofsituations, such as through small spaces or openings. Moreover, datatransmission through fiber optic links is less susceptible to noise,such as the electromagnetic energy associated with electric motors andtransformers, and therefore presents an improved signal path as comparedto more traditional copper (e.g., coax) cable solutions. For example,ground loop effect, wherein differences between grounding potential in aroof top installation and a basement installation, may result insignificant electromagnetic interferences penetrating coaxial cableslinking such installations. As one skilled in the art will appreciate,such interference is not well tolerated by analog circuits. The use ofthe preferred optical fiber, digitally linking these installations,negates this interference.

It should be appreciated that the preferred embodiment configuration,providing digital communication between an IDU subsystem and an ODUsubsystem, is not itself without challenges. For example, the abovedescribed preferred embodiment configuration, wherein only digitalsignal processing is provided for in the IDU subsystem and all analogsignal processing is preferably provided for in the ODU subsystem,results in the separation of circuitry requiring a well-controlledtiming relationship transparently therebetween. Therefore, although thepreferred embodiment ODU subsystem is substantially only burdened withperforming RF related duties, control and/or timing challenges arepresented with respect to the ODU to IDU interface.

Preferred embodiments of the present invention utilize synchronouscommunication between IDU subsystem 201 and ODU subsystem 202 tosynchronize digital communication within fiber link 240 and operation ofODU subsystem 202. For example, a portion of the digital data streamprovided between IDU subsystem 201 and ODU subsystem 202 preferablyincludes control data of the present invention, such as synchronizingdata in the form of timing bits, training sequences, and/or the like.For example, such timing and training may be carried out by timingcircuitry generally illustrated by blocks 251 and 252 of FIG. 2.

The present invention may utilize various forms of synchronous protocolsin communications between IDU subsystem 201 and ODU subsystem 202specifically tailored for addressing particular system attributes. Forexample, in a preferred embodiment wherein multiple ODU subsystems areprovided data communication via fiber optic cable 240, a multiplexedsynchronous protocol, such as SONET, may be utilized to both addresstiming issues as well as to provide communication of data between anumber of subsystems.

Directing attention to FIG. 3, an embodiment of the present inventionleveraging the relatively high data capacity of the fiber optic linkbetween an IDU subsystem and an ODU subsystem of the present inventionis shown. Specifically, wireless communication system 300 is configuredto couple a plurality of ODU subsystems, ODU subsystems 202 and 302, toan IDU subsystem, IDU subsystem 301, via fiber optic cable 240.Accordingly, wireless communication system 300 may be utilized to servea relatively large service area and/or a larger number of subscribersthan the configuration of FIG. 2 by properly orienting ODU subsystems toilluminate (communicate with) desired areas/subscribers. It should beappreciated that the multiple ODU subsystems of the illustratedembodiment, which may number more than the two represented in FIG. 3,all utilize data communication via fiber optic cable 240, therebyallowing their deployment with little or no cabling burden beyond thatfor deployment of a single ODU subsystem. Moreover, the aforementionedbenefits associated with the use of fiber optic cable continue to berealized.

According to one embodiment as illustrated in FIG. 3, the plurality ofODU subsystems are interconnected in “daisy chain” fashion. For example,ODU subsystem 302 is coupled directly to IDU subsystem 301 via fiberoptic cable 240 at fiber interface 326, while ODU subsystem 202 iscoupled to ODU subsystem 302 via fiber optic cable 341 at fiberinterface 226, thereby providing an indirect connection to IDU subsystem301 via fiber optic cable 240. Accordingly, fiber interface 326, andperhaps fiber interface 226, may be provided with multiport data routingand/or switching functionality. For example, in an embodiment utilizingthe above mentioned SONET protocol in data communications between an IDUsubsystem and ODU subsystems, fiber interface 326 may be provided withadd/drop multiplexer (ADM) functionality.

It should be appreciated that in providing the embodiment of FIG. 3, IDUsubsystem 301 and ODU subsystems 202 and 302 may be configuredsubstantially as described with respect to the embodiment of FIG. 2. Forexample, ODU subsystems 202 and 302 may include substantially the samecomponents and function substantially as described above with respect toODU subsystem 202, except that the aforementioned multiport data routingand/or switching functionality may be added. Of course, ODU subsystem202 of FIG. 2 may include such multiport data routing and/or switchingfunctionality, although perhaps not utilized in that particularconfiguration, if desired. Accordingly, a single ODU subsystemconfiguration may preferably be used which allows for increasedmanufacturing and handling efficiencies and provides for expansion ofdeployments by adding ODU subsystems and activating multiport datarouting and/or switching functionality. Additionally or alternatively,ODU subsystems without multiport data routing and/or switchingfunctionality may be utilized in multipoint hub configurations similarto that of FIG. 3. This may be carried out by disposing a router orswitch in fiber optic cable 240 for coupling a plurality of ODUsubsystems.

The illustrated embodiment of FIG. 3 includes IDU subsystem 301 adaptedto include scaling with respect to the circuitry described above withrespect to IDU subsystem 201. Accordingly, IDU subsystem 301 of theillustrated embodiment includes repetition of circuitry described abovewith respect to IDU subsystem 201 with fiber interface 316 providingcombining and separation of the data for communication via fiber opticcable 240. Such circuitry may be included to provide parallel processingof the data associated with multiple subscriber units, to serve multipleisolated networks, to accommodate multiple network interfaces, etcetera.Of course, other configurations of an IDU subsystem may be adoptedaccording to the present invention. For example, the circuitry of IDUsubsystem 201 of FIG. 2 may be sufficient to process the data ofmultiple ODU subsystems coupled thereto, according to an embodiment ofthe present invention.

Also shown in FIG. 3 is optional fiber optic cable 340 coupling IDUsubsystem 301 and ODU subsystem 202. For example, fiber interfaces 226and 316 may be adapted to include multiport data routing and/orswitching functionality to provide a resilient packet ring topology orthe like. Such a topology provides redundancy in the data link suitablefor tolerating a single point of failure at any point in the ring.Additionally or alternatively, such additional links between the IDUsubsystem and ODU subsystems may be utilized to increase the datacapacity therebetween.

Although the present invention and its advantages have been described indetail, it should be understood that various changes, substitutions andalterations can be made herein without departing from the spirit andscope of the invention as defined by the appended claims. Moreover, thescope of the present application is not intended to be limited to theparticular embodiments of the process, machine, manufacture, compositionof matter, means, methods and steps described in the specification. Asone of ordinary skill in the art will readily appreciate from thedisclosure of the present invention, processes, machines, manufacture,compositions of matter, means, methods, or steps, presently existing orlater to be developed that perform substantially the same function orachieve substantially the same result as the corresponding embodimentsdescribed herein may be utilized according to the present invention.Accordingly, the appended claims are intended to include within theirscope such processes, machines, manufacture, compositions of matter,means, methods, or steps.

What is claimed is:
 1. A system providing broadband access to one ormore subscribers, the system comprising: an indoor unit comprising afirst digital interface for communicating digital subscriber databetween the one or more subscribers and the indoor unit and a firstfiber optic interface for communicating, via a fiber optic cable, thedigital subscriber data between the indoor unit and an outdoor unit thatcomprises a second fiber optic interface for communicating, via thefiber optic cable, the digital subscriber data between the indoor unitand the outdoor unit and a wireless interface for communicating wirelesssubscriber data between the outdoor unit and a network, where the indoorunit provides only digital signal processing of the digital subscriberdata and the outdoor unit provides all analog signal processing of thedigital subscriber data performed by the system.
 2. The system of claim1 where the first digital interface is an Ethernet interface.
 3. Thesystem of claim 1 where the fiber optic interface and the second fiberoptic interface communicate, via the fiber optic cable, digitalsynchronous communication data between the indoor unit and the outdoorunit.
 4. The system of claim 3 where timing bits are simultaneouslytransmitted with data bits via the fiber optic able between the indoorunit and the outdoor unit.
 5. The system of claim 4 where the timing bitare utilized to synchronize communication of the digital subscriber databetween the indoor unit and the outdoor unit.
 6. A system providingbroadband access to one or more subscribers, the system comprising: anoutdoor unit comprising a wireless interface for communicating wirelesssubscriber data between the outdoor unit and a network and a first fiberoptic interface for communicating, via a fiber optic cable, digitalsubscriber data between the outdoor unit and an indoor unit comprising asecond fiber optic interface for communicating, via the fiber opticcable, the digital subscriber data between the outdoor unit and theindoor unit and a first digital interface for communicating digitalsubscriber data between the one or more subscribers and the indoor unit,where the indoor unit provides only digital signal processing of thedigital subscriber data and the outdoor unit provides all analog signalprocessing of the digital subscriber data performed by the system. 7.The system of claim 6 where the first digital interface is an Ethernetinterface.
 8. The system of claim 6 where the fiber optic interface andthe second fiber optic interface communicate, via the fiber optic cable,digital synchronous communication data between the indoor unit and theoutdoor unit.
 9. The system of claim 8 where timing bits aresimultaneously transmitted with data bits via the fiber optic ablebetween the indoor unit and the outdoor unit.
 10. The system of claim 9where the timing bit are utilized to synchronize communication of thedigital subscriber data between the indoor unit and the outdoor unit.11. A method for providing broadband access to one or more subscribers,the system comprising: receiving, at an indoor unit via a first digitalinterface, digital subscriber data from the one or more subscribers;performing digital signal processing on the received digital subscriberdata; transmitting, from the indoor unit via a fiber optic interface,the digitally processed digital subscriber data from the indoor unit toan outdoor unit that receives the digitally processed digital subscriberdata, performs analog signal processing on the digitally processeddigital subscriber data, and transmits wireless subscriber data to anetwork, where the indoor unit provides only digital signal processingof the digital subscriber data and the outdoor unit provides all analogsignal processing of the digital subscriber data performed by thesystem.
 12. The method of claim 11 where the first digital interface isan Ethernet interface.
 13. The method of claim 11 where transmitting,from the indoor unit via a fiber optic interface, the digitallyprocessed digital subscriber data comprises transmitting digitalsynchronous communication data between the indoor unit and the outdoorunit.
 14. The method of claim 13 where transmitting, from the indoorunit via a fiber optic interface, the digitally processed digitalsubscriber data comprises simultaneously transmitting timing bits withdata bits via the fiber optic able between the indoor unit and theoutdoor unit.
 15. The method of claim 14 where the timing bit areutilized to synchronize communication of the digital subscriber databetween the indoor unit and the outdoor unit.
 16. A method for providingbroadband access to one or more subscribers, the system comprising:receiving, at an outdoor unit via a wireless interface, wirelesssubscriber data; converting the wireless subscriber data to digitalsubscriber data; and transmitting, from the outdoor unit via a firstfiber optic interface, the digital subscriber data to an indoor unitthat receives the digital subscriber data via a second fiber opticinterface, performs digital signal processing on the digital subscriberdata, and transmits, via a first digital interface, the processeddigital subscriber data to the one or more subscribers, where the indoorunit provides only digital signal processing of the digital subscriberdata and the outdoor unit provides all analog signal processing of thedigital subscriber data performed by the system.
 17. The method of claim16 where the first digital interface is an Ethernet interface.
 18. Themethod of claim 16 further comprising: transmitting digital synchronouscommunication data between the indoor unit and the outdoor unit.
 19. Themethod of claim 18 further comprising: simultaneously transmittingtiming bits with data bits via a fiber optic able between the indoorunit and the outdoor unit.
 20. The method of claim 19 where the timingbit are utilized to synchronize communication of the digital subscriberdata between the indoor unit and the outdoor unit.